Trayvon Martin's family said he was confronted, then shot and killed by a neighborhood watchman.

The Sanford Police Department said it won't release the 911 tape in the shooting because the investigation is still ongoing.

Martin's family members said they believe the tape will help support their claim that the man who shot Martin was a loose cannon.

Martin was visiting his father and stepmother in Sanford on Feb. 26 when the shooting happened. George Zimmerman, who is part of the Neighborhood Watch program, confronted him while he was walking back to their home from a convenience store, according to the family's attorney, Natalie Jackson.

"This guy was not arrested," said Martin's mother, Sybrina Fulton. "I do not understand. As a mother my heart is broken."

Zimmerman had called 911 because he thought the teen looked "suspicious," but didn't wait for police officers to arrive before confronting him. The family attorney said in a news release that at some point, Zimmerman shot him.

Sanford Police said the 911 tape appears to support Zimmerman's claim that he was struggling with Martin and fired on him in self defense.

The family said they want to hear the 911 tape for themselves.

Martin's family said they believe the tape will support their belief that a dispatcher told Zimmerman not to approach Martin.

"The 911 tape will show it's going to be riveting," said family attorney, Benjamin Crump. "Police have said they told him not to do anything. He went on his own volition to confront this kid."

The attorneys demanded that Zimmerman be arrested and charged with Martin's death.

"My son left Sanford Florida in a body bag," said Martin's father, Tracy Martin. "While George Zimmerman went home to to go to sleep in his own bed. It's senseless and the police in Sanford Florida isn't giving any answers and we actually feel that justice hasn't been served and isn't being served."

The attorney said the teen was not carrying any weapons -- just a bag containing skittles and a can of iced tea.